Laravel Pub-Sub package use transactional outbox pattern

When an event is sent to the broker, the event is stored in the database, after which the event is sent to the broker. If the event was successfully sent to the broker, we mark that the event was successfully sent.

When subscribing an event, we listen to the event from the broker. When receiving an event, we store it in the database. After saving to the database, we send an internal event for processing.

The goal of the library is to decide the consistency of data between services, the order in which the message is sent, idempotency.

Currently, the broker is Redis. In the future we will add other brokers message.

Installation

You can install the package via composer:

composer require ludovicose/transaction-outbox

The package will automatically register itself.

You can publish the migration with:

php artisan vendor:publish --provider="Ludovicose\TransactionOutbox\PackageServiceProvider" --tag="migrations"

After the migration has been published you can create the table by running the migrations:

php artisan migrate

You can publish the config-file with:

php artisan vendor:publish --provider="Ludovicose\TransactionOutbox\PackageServiceProvider" --tag="config"

Usage

Publish Event

Create event file and implements by ShouldBePublish interface. If the ShouldBePublish interface is implemented, then the event automatically goes to the broker Set channel name. Channel name is the name of the event that will be sent to the broker

namespace App\Events;

use Ludovicose\TransactionOutbox\Contracts\ShouldBePublish;

class PostCreatedEvent implements ShouldBePublish 
{
    ...

    public function getChannel(): string
    {
        return 'channelName';
    }
    ...
}

To send an event to the broker, you need to run the command

event(new PostCreatedEvent($someData));

Subscribe

Add a channel name to the config file to understand which event to listen for. These channel names can be used as internal events.

return [
    ...
    'subscribe_channels' => [
        'channelName'
    ],
    ...
];

Run command in console t listen event in broker.

$ php artisan events:listen

Add a channel name to the EventServiceProvider file to listen for the event that came from the broker.

namespace App\Providers;

... 

class EventServiceProvider extends ServiceProvider
{

    protected $listen = [
        ... 

        'channelName'                  => [
            SomeListener::class
        ]

        ...
    ];
}

In handle method you get the data that came from the broker

namespace App\Listeners;

class SomeListener
{

    public function handle($event)
    {
        // $event data in event
    }
}

Resubmitting events

If the event did not get into the message broker, then you can resend it with the command below, indicating the start date and end date

$ php artisan events:repeat 2022-12-12

Http request

We can also log http requests. When sending a request, we save it with ourselves and upon receiving a response, we note that the request was successfully completed.

To register http requests, you must enable the option in the config file

return [
    ...
    'enable_request_log' => true
    ...
];

Resubmitting request

If the http request failed, then it can be resent with the command below, specifying the start date and end date

$ php artisan request:repeat 2022-12-12

Resend erroneous data from the queue

If we get an error while processing data from the queue, then this data goes to the queue (serviceName.errors).

To resend data from the queue (serviceName.errors) we need to run the command:

$ php artisan events:resend-errors

In the configuration file you can specify the name of the queue where the errors will be stored

return [
    ...
    'error_queue' => 'errors'
    ...
];

Clear event in DB

If you do not clean the database from the event, then the entries in the database can increase. To clean up old entries, you can run the command:

$ php artisan events:clear

In the config file, you can specify a day after which records will be deleted

return [
    ...
    'delete_last_event_in_day' => 10
    ...
];

QUEUE

Add queue.php config rabbitmq

return [
    ...
    'connections' => [
        ... 
         'rabbitmq' => [
            'driver'     => 'rabbitmq',
            'connection' => 'default',
            'queue'      => env('RABBITMQ_QUEUE', 'default'),
        ],
        ... 
    ]   
    ...
];

License

The MIT License (MIT). Please see License File for more information.